Question

Which of the following anticancer drugs are competitive inhibitors of tyrosine kinase ?

• A. Imatinib and sunitinib
• B. Letrozole
• C. Bicalutamide
• D. Fulvestrant

Answer 1

The Correct Option is A

Quick rule: if the drug ends in -nib, it usually inhibits a kinase, and the small-molecule TKIs compete with ATP at the kinase active site.
Scan the options: imatinib and sunitinib both end in -nib, so they are tyrosine kinase inhibitors; imatinib hits BCR-ABL in CML, sunitinib is a multi-kinase agent for GIST and renal cancer. The remaining options work on hormone pathways: letrozole blocks aromatase, bicalutamide blocks the androgen receptor, and fulvestrant degrades the estrogen receptor. None of those touch tyrosine kinase.
Mechanism reminder: these -nib drugs sit in the ATP pocket and stop phosphorylation of downstream targets, which is why they are called competitive inhibitors.
Answer: imatinib and sunitinib.
Reference: targeted cancer chemotherapy.